Don't know much inside info, all I know is what the 16th amendment to the Constitution says (posted below). The following link has some annotations on the specifics of the amendment.
All
I really need to know is, if you don't pay your taxes, the IRS will prosecute and send you to jail.
http://caselaw.lp.findlaw.com/data/constitution/amendment16/
[SIZE=+1]The Congress shall have power to lay and collect taxes on incomes, from whatever source derived, without apportionment among the several States, and without regard to any census or enumeration. [/SIZE]